X-Ray Production in theLShell of Copper by 25- to 1700-eV Protons

$L$-shell x rays of copper were produced by stopping 25- to 1700-keV protons in a thick target. X rays associated with the production of initial vacancies in the $L_{\mathrm{III}}$ shell were isolated by an absorption technique. Total $L$-shell x-ray yield is presented, as well as yield, production, and ionization cross sections for the $L_{\mathrm{III}}$ shell. The Born approximation is compared with the experimental ionization cross section and is found to be consistently high over the whole range of bombarding energies.